If the statement Some animals are birds is given as false, then which of the following statements can be immediately inferred to be false?

All animals are birds must be false once the I proposition is false.

Some animals are birds is an I claim declared false.

By subalternation the universal A implies its subaltern I.

So if I is false the corresponding A cannot be true.

The A form here is All animals are birds, hence derivably false.